首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1607469篇
  免费   49019篇
  国内免费   21444篇
化学   705275篇
晶体学   20929篇
力学   79844篇
综合类   622篇
数学   249055篇
物理学   395581篇
无线电   226626篇
  2021年   19015篇
  2020年   21257篇
  2019年   21546篇
  2018年   15820篇
  2017年   13991篇
  2016年   33885篇
  2015年   26510篇
  2014年   38833篇
  2013年   86371篇
  2012年   48259篇
  2011年   44199篇
  2010年   45615篇
  2009年   50807篇
  2008年   45135篇
  2007年   40853篇
  2006年   48188篇
  2005年   38921篇
  2004年   38976篇
  2003年   36651篇
  2002年   37663篇
  2001年   36400篇
  2000年   32836篇
  1999年   31169篇
  1998年   29507篇
  1997年   29108篇
  1996年   28973篇
  1995年   26317篇
  1994年   25728篇
  1993年   24625篇
  1992年   24463篇
  1991年   24415篇
  1990年   22984篇
  1989年   22368篇
  1988年   21462篇
  1987年   20167篇
  1986年   18955篇
  1985年   25436篇
  1984年   26480篇
  1983年   22369篇
  1982年   23737篇
  1981年   22878篇
  1980年   22125篇
  1979年   22021篇
  1978年   23227篇
  1977年   22843篇
  1976年   22411篇
  1975年   21062篇
  1974年   20669篇
  1973年   21128篇
  1972年   15343篇
排序方式: 共有10000条查询结果,搜索用时 437 毫秒
91.
92.
Sun  J.  Yuan  H. 《Experimental Mechanics》2021,61(3):565-580
Experimental Mechanics - Temperature gradients significantly affect the material fatigue process. A reliable and robust test procedure is needed for quantifying the effects of temperature gradients...  相似文献   
93.
Journal of Optimization Theory and Applications - Direct optimization of many-revolution spacecraft trajectories is performed using an unconstrained formulation with many short-arc, embedded...  相似文献   
94.
Russian Physics Journal - The temperature dependences of the linear dielectric permittivity ε′ and the third harmonic coefficient γ3ω for nanocomposites obtained by embedding a...  相似文献   
95.
96.
97.
Recent advancements in isolation and stacking of layered van der Waals materials have created an unprecedented paradigm for demonstrating varieties of 2D quantum materials. Rationally designed van der Waals heterostructures composed of monolayer transition-metal dichalcogenides (TMDs) and few-layer hBN show several unique optoelectronic features driven by correlations. However, entangled superradiant excitonic species in such systems have not been observed before. In this report, it is demonstrated that strong suppression of phonon population at low temperature results in a formation of a coherent excitonic-dipoles ensemble in the heterostructure, and the collective oscillation of those dipoles stimulates a robust phase synchronized ultra-narrow band superradiant emission even at extremely low pumping intensity. Such emitters are in high demand for a multitude of applications, including fundamental research on many-body correlations and other state-of-the-art technologies. This timely demonstration paves the way for further exploration of ultralow-threshold quantum-emitting devices with unmatched design freedom and spectral tunability.  相似文献   
98.
Synthetic active matters are perfect model systems for non-equilibrium thermodynamics and of great potential for novel biomedical and environmental applications. However, most applications are limited by the complicated and low-yield preparation, while a scalable synthesis for highly functional microswimmers is highly desired. In this paper, an all-solution synthesis method is developed where the gold-loaded titania-silica nanotree can be produced as a multi-functional self-propulsion microswimmer. By applying light, heat, and electric field, the Janus nanotree demonstrated multi-mode self-propulsion, including photochemical self-electrophoresis by UV and visible light radiation, thermophoresis by near-infrared light radiation, and induced-charge electrophoresis under AC electric field. Due to the scalable synthesis, the Janus nanotree is further demonstrated as a high-efficiency, low-cost, active adsorbent for water decontamination, where the toxic mercury ions can be reclaimed with enhanced efficiency.  相似文献   
99.
Nikazad  T.  Karimpour  M. 《Numerical Algorithms》2021,86(3):1265-1284
Numerical Algorithms - This paper considers different versions of block-column iterative (BCI) methods for solving nonnegative constrained linear least squares problems. We present the convergence...  相似文献   
100.
Journal of Applied Mechanics and Technical Physics - Implicit finite-volume predictor-corrector algorithms based on the splitting method are proposed for the numerical solution of the...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号